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(No Modell) G. BONKER.

SLIDE VALVE.

No. 374,289. l Patented Deo. 6, 1887..

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f ii A if M j v W @MM/WW@ Mmmm -sponding cylinder-face. is semi-cylindrical.

UNITED STATES PATENT OFFICEo GEORGE BONKER, 'OF SEDALIA, MISSOURI.

SLIDE-VALVE.

SPECIFICATION forming para ef Letters Patent No. 374,289, dated December 6, 1887.

Application filed August G, 1886. Serial No. Ql0,200.

To aZZ whom, it may concern:

Be it known that I, GEORGE BONKER, of Sedalia, Pettis county, in the State of Mis souri, have invented a new and `useful Improvement relating to Slide-Valves, of which the following is a full and exact description.

The invention may apply to steam or .gas engines of any size and adapted for use in any situation. It is more particularly intended for locomotives and other steam-engines of quick action. I will describeit as so applied. The valve may be of any size desired to give free movement of the steam. The pressure of the steam is nearly balanced. The valve is allowed to receive pressure onlyT sufficient to hold it in steam-tight contact with its seat.

Many efforts have been made to employ steam-valves on which the' pressure of the steam shall be nearly balanced. Nearly all require special constructions of the other parts of the engine, and all involve complications which confuse the attendant. They require more engineering skill than is readily and economically at hand. I

Another objection which goes far to neutralize the advantages of the balancing principle lies in the difficulty of adjusting the packing. If it is too -slack at any point, the valve leaks and is impracticable. If too tight, as is usually the case, it subjects the engine to a load in working the valve which is liable to approximate or even to exceed that which would be experienced if the valve were worked under the full steam-pressure.

My valve has a plane face corresponding to the ordinary slide-valve and works on a correrlhe back of the valve I employ a removable casing correspondingly formed to match the semi-cylindrical valveintroduced in the steam` chest with facilities for holding it firmly with out springing it and for removing it at will t0 allow of examination and repairs. The back of the valve is provided with packing, which excludes the steam from the principal portion of the back. I provide for adjusting the tension of the packing `and springs with unusual exactness after all the parts are in place. The valve is connected with the valve-stem by nuts andjam-nuts, which allow it to adjust itself to wear or to imperfections in the workman` ship.

(No model.)

'through the valve and adjacent portions. Fig.

2 is a transverse section on the linea` in Fig. l. Fig. 3 is a corresponding section on the line 'yy in Fig. l. Fig. A isaview from above, showing the packing-rings alone.

Similar letters of reference indicate corresponding parts in all the gures where they occur.

A is a portion of the cylinder-face, serving as the valve-seat. The three ports therein perform the usual functions, the two exterior receiving and discharging steam, respectively, for the two ends of the main cylinder, (not represented) While the central port communicates with an exhaust-passage (not represented) which is open to the atmosphere.

The steam may be admitted -to the steamchest in the ordinary manner.

A indicates the main body of the steamchest, .and B the removable cover therefor, which is strongly bolted along its edge in the ordinary or any suitable manner.

D is the valve, of semicircular cross section, grooved to receive packing.

I willdesignate the entire packing by the letter M. The packing extends circumferentially across the semi-cylindrical back of the valve in two parallel lines, M', one near each end of the valve. rIhe space inclosed by this packing is relieved from steam-pressure. 'Ihe construction relieves nearly the entire valve from pressure.. Only a sufficient portion near each end receives pressure to hold the valve with gentle force against its seat A.

E is a removable-casing, which performs important functions. It is of such form that it braces against the interior of the steamchest A in all directions, so that the casing cannot move much out of place. It is arched. The hollowsemi-cylindrical under surface is smoothly finished to match the back of the valve. Each side is `formed with a deep iange,

ridge, or wing, E', which receives set-screws B, tapped throughV the steam-chest cover B. The force of these screws holds the casing IOC tightly upon its seat without possibility of changing the form of the casing E, no matter how strongly the screws B are forced down. The form of the casing E provides two liberal channels, e, through which the steam may flow freely from one end of the steam-chest to the other, allowing each end' of the cylinder to receive steam with the full boiler-pressure.

The packing M may be of any ordinary or suitable material. If of metal, it may be formed in any number of parts matched together in any ordinary or suitable manner to insure steam-tight contact with easy movement. I propose to use the form commonlyknown as Dunbars5 but instead of holding the packing bythe force of the steam I set it mechanically. I employ backing-springs and adjusting means therefor, which will now be described. There are holes cored orotherwise produced, in the ends of the valve D. G are screws tapped into these cored openings cZ and resting their outer ends against springs H, which act on the inner or back surface of the packing M. By reaching into a hole d with a suitable fork, wrench, or other convenient device and engaging the squared inner endv of the corresponding screw G, it may be turned and adjusted to set the springs H, and consequently the packing M, out with any required degree of force, or to relax the force, if desired. J am-nuts G, fitted on the screws G, serve to hold the latter rigidly after the correct position is determined.

My valve D, with its casing E, may be applied to engines already in use. The form of the parts allows the steam to flow freely from one end to the other of the steam-chest. The valve works with slight resistance, and gives an induction and eduction passage in the ordinary form. It requires no extra skill or care in setting or attending to the valve.

I is an oil-cup extending through the steamchest cover B and tapped into the back of the casing E. A smaller passage, i, extends through the casing. oil-cup is screwed down with absolute tightness into the casing E. An elastic gasket under the collar I of the oil-cup keeps the orifice through the cover B steam-tight. The oil supplied through the cup I flows down through 5o the stem and fills the thin chamber on the back of the valve within the packing M. This oilchamber, moving with the valve,lubricates the surfaces without waste. The orifices d, being constantly open, allow the wrench to be ap- 55 plied to the screws G to adjust them without difficulty. The wings E being close to the with its packing M, inclosing an extended oil- 7o chamber, in combination with each other and with the oil-cup I, cylinder A, steam-chest and cover B, all arranged for joint operation substantially as herein specied.

In testimony whereof I have hereunto set my hand, at Sedalia', Missouri, this 29th day of July, 1886, in the presence of two subscribing witnesses.

GEO. BONKER. Witnesses:

Louis DEUTsoH, CHAs. Koook.

The hollow stem of the 45 

